The present invention relates to wrenches, and more specifically, to a tension meter and wrench arrangement that displays the tension of the wrench upon operation of the wrench.
When operating a wrench, the user can only estimate the tension of the wrench by experience. However, it is not accurate to estimate the tension of the wrench by experience. When applied an excessively high torsional force to the wrench, the wrench may be forced to break, causing an accident. In order to eliminate this problem, wrenches with tension indicator means are developed. FIGS. 7 and 8 show two ratchet wrenches with electronic type tension indicator means according to the prior art. Because the electronic type tension indicator means occupies much installation space, the installation of the electronic type tension indicator means affects the convenience of the operation of the wrench. Further, because the electronic type tension indicator means is disposed outside the wrench, it tends to be damaged accidentally.
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a tension meter and wrench arrangement, which accurately indicates the tension of the wrench during the operation of the wrench. It is another object of the present invention to provide a tension meter and wrench arrangement, which requires less installation space in the wrench. It is still another object of the present invention to provide a tension meter and wrench arrangement, which has means to protect the electronic parts thereof when not in use. According to one aspect of the present invention, the tension meter and wrench arrangement comprises a resistance type tension meter and an integrated device installed in a wrench, the integrated device providing a voltage output corresponding to the variation of resistance detected by the tension meter and converting the voltage output into digital signal for display through a display screen, the wrench having a sliding sleeve adapted for protecting the integrated device. According to another aspect of the present invention, a sliding sleeve is axially slidably mounted on the handle of the wrench and adapted for protecting the integrated device when the wrench is not in use.